Nice place, perfect for short stay.
I'm a video blogger and I did a bit of scouting:
*Regarding the flat itself: Did not see or hear from the owners at all, which I preferred!
*Internet was a bit iffy but you can get a Baht299 3G unlimited data card at the airport.
*The place is not that close to BTS and although the area seems a bit dodgy, it's very safe.
*Nice pool and gym on 25th floor! Take some work out clothes and swim suit! Host provides towels and bedding.
The area:
*One BTS stop further down (Onut Station) station you will walk into Tesco, a big and CHEAP supermarket for all other essentials. (Including good cheap wine!) This BTS also has a relatively good foreign exchange shop.
*There a new 7/11 just 50 meters from the outside gate to the complex...very convenient! Get your heavy stuff like drinking water there.
*Closest BTS is at least 1km+ away...you will sweat so take a hat or umbrella.
*Walking out and to the BTS you will pass a Tom Tom's coffee shop on the other side of the road, take the footbridge and pass the coffee shop walking into the complex and to the right. You will find a HUGE beer garden type outdoor area with at least 20+ restaurants and a couple of bars to choose from. The hotel adjacent to it also has a very nice (but expensive) sky bar on the 46th floor.
*The building of the flat has a coin laundromat on the ground floor, but for Baht130 you can have all your stuff washed and dried and folded and dont need to waste any time doing it yourself! Instead of taking the footbridge to Tom Tom's, turn left into the alley, walk straight about 150m to a T junction, just on the other side of the road to the left 10m maybe you will see a small laundromat next to the ATM...super lovely owner with enough English to get your clothes done. (And smells really nice after) I did a weeks worth of laundry plus a towel for Baht130. (She might be closed on Wednesdays tho)
*When you walk out to the main road past the 7/11 and turn left onto the main road, about 10 meters down there is a street vendor selling Gloy Bing (BBQ Banana) in the afternoons, it's good and safe ;) Baht20 for four bananas.
*There is an MMA gym near the BTS, but you will have to Google the exact location
*Taxi late at night from Sukumvit Soi 4 area will cost you around 300Baht back to the flat (200Baht is you are really lucky)
*Taxi from the airport to the flat Baht400 flat rate, or meter, but you will pay the tolls and it works out to about Baht450+ in good traffic.

More tips on Bangkok check out my page lvtw.tv :)
PS: Bangkok is my favorite city in the world!